I think this only really happens on consoles. The typical console gamer will rent a game and blow through it in a few months (or buy it and sell it back afterwards), never touching it for a second playthrough or more multiplayer. This is only strengthened by the fact that console multiplayers have a very limited life because they have company-run servers that need to be maintained. PC gamers, on the other hand, typically keep their games forever, and it shows. Every single ancient multiplayer component I've ever played on a PC game, from a few years old to decades old, has had at least a few lag-free players ready to go.
However, this doesn't make the PC superior--it merely means game developers need to have console play-styles in mind more when they develop their multiplayer. Co-op should be separate and, preferrably, on a split-screen. When it's integrated into the singleplayer, it shouldn't be easier than singleplayer. This was one thing Brink actually got right (besides the crap AI that threw its intended design out the window). Games that rely so heavily on multiplayer to be completed should be advertised very strongly as such, and perhaps even deliberately kept alive with patches and DLC. Players that want a game-enriching multiplayer, like in Demon's Souls, but who don't have enough money to jump on all these games on release, are going to have to accept that it just isn't possible on consoles until developers start accommodating the blow-through-a-game style. Which sucks, because if they don't have the money to jump on all these games, I doubt they can go buy a gaming PC.